When it comes to emergency warning and mass notification much of the conversation lately seems to focus on social media and other relatively recent technological developments such as cellular communications and text messaging. However, the ability of high-powered siren/speaker arrays to support wide-area emergency warning and instructions in real time continues to represent an essential layer of emergency communications. Beyond merely providing redundancy to support other modes of emergency communication, outdoor sirens remain an integral component of any overall emergency warning and public alerting strategy.